12 Apr (NucNet): French state-controlled utility EDF will have to inspect more weldings at the Flamanville-3 nuclear plant under construction in northern France after flaws were discovered in the weldings of the reactor’s secondary circuit, nuclear regulator ASN said.
ASN said it had carried out an inspection at the Flamanville-3 site on 10 April and found that “the organisation and the working conditions during the end-of-production controls have generally hindered the quality of the controls”. It said controls would now have to be extended to other circuits in the plant.
According to ASN, inadequate monitoring of these services by EDF and reactor builder Framatome did not make it possible to identify and remedy problems. “Some defects are still under investigation in order to understand the causes of their non-detection during the end of manufacturing controls,” ASN said.
EDF said on 10 April that problems with Flamanville’s weldings were worse than first expected and may impact the cost and startup of the project.
The utility said it will comment on the startup schedule at the end of May, after it has verified all 150 weldings in the secondary circuit that conducts steam from the steam generator to the plant’s turbines.
“ASN considers that EDF will have to extend its controls to other circuits,” the regulator said in a statement.
Earlier this week EDF announced that it had discovered “certain quality deviations” on the welding of pipes in the main secondary system of the Flamanville-3 EPR.
EDF said at the time it had told ASN of the discovery, but had yet to determine whether the unit’s startup, scheduled the end of this year, will be delayed.
EDF said the discovery was made during an initial comprehensive inspection of the plant. The inspection is a regulatory requirement before startup. It includes the examination of the welds of the primary and secondary systems and allows an initial “reference state” to be established for the plant before its entry into operation, EDF said.
The loading of nuclear fuel at Flamanville-3 is scheduled for the end of the 2018. Construction costs for the project are €10.5bn, EDF said. An estimate of the cost in July 2011 was €8bn.
In February EDF said some weldings on Flamanville-3’s secondary cooling circuit did not meet specifications, but the issue would not affect safety or the schedule to start up the plant at the end of 2018.
